If the way the Nets played Monday night against the Pacers is any indication of what they’ll look like without Brook Lopez, things won’t be getting better anytime soon.

In their first game since Lopez was lost for the year with a fractured fifth metatarsal in his right foot, the Nets were blasted off their home floor by the Eastern Conference leading Pacers, 103-86, in front of a sellout crowd of 17,732 inside Barclays Center.

“It’s getting very close to just accepting losing,” coach Jason Kidd said after a lengthy delay in appearing for his postgame press conference. “We’re kind of getting comfortable with losing. We’ve got to make a stand with that, because when things get tough do we just give in? Most of the time right now, we do.”

The Nets (9-18), a team that entered this season with championship aspirations, have now lost three straight and four of their last five. They are now tied with the Knicks for third place in the horrid Atlantic Division and sit two games behind the Celtics for eighth place in the equally dismal Eastern Conference.

After a hot start, the Nets simply couldn’t make a shot, looking lost without the option of tossing the ball into their All-Star center. Instead, they looked out of sorts all night, led by a dreadful performance from Deron Williams, who went 3-for-9 from the field and finished with nine points, eight assists and four turnovers in 32 minutes.

“I need to play better,” Williams said, adding that he was fine after appearing to tweak his left ankle — the one that’s already cost him 11 games this season — shortly before exiting the game for good in the fourth quarter. “I need to be more aggressive for us to have a chance, especially with Brook going down.

“That’s what I talked about, stepping up, and so tonight was just a bad game for me. [I was] throwing the ball all over the place [and] couldn’t hit a shot, so it took my aggressiveness away and I think I played into what they were trying to do.”

Paul Pierce had his own issues, going 0-for-7 from the field in 15 minutes before he was ejected with 4:22 to go in the third for hitting George Hill around the neck after the Pacers’ point guard picked off an errant Joe Johnson pass and took off down the floor. After a short review, the original flagrant foul call was upgraded to a flagrant 2, sending Pierce to the showers early.

“No. That’s a part of the game,” Hill said when asked if Pierce’s foul was a cheap shot. “Hard fouls are a part of the game. I’ve been in that position a lot, my whole life. It’s fine. [I] get back up and don’t let it faze me.”

Pierce is likely to receive a fine from the league for the foul, but it is unlikely he would receive a suspension that would prevent him from playing in Wednesday’s Christmas Day matinee against the Bulls in Brooklyn. Both Pierce and Kevin Garnett, who finished with 12 points and five rebounds in 18 minutes after starting at center in place of Lopez, didn’t speak to reporters after the game.

It initially looked as if the Nets might rally together and give the Pacers (23-5) a game after beginning the game 7-for-11 from the field and taking an early 16-10 lead on an Andray Blatche jumper with 5:38 remaining in the opening quarter.

But the Nets would go on to miss their final 10 shots of the quarter as the Pacers went on a 9-1 run to take a 19-17 lead after one that, outside of the Nets briefly regaining the lead for 65 seconds early in the second, they would never relinquish.

“It was one of those types of games that the team that grinded the hardest was going to prevail,” said Jason Terry, who scored 11 points — including three 3-pointers — while playing the final 15:08 in his first game since Nov. 20 because of a sore left knee. “As the game got tighter, as each possession got closer, they were the team that outlasted us, and that just can’t happen.”

As it often has this season, it was the third quarter that put the Nets in a hole they couldn’t recover from, as the Pacers opened the quarter with a 17-4 run and never looked back, at one point leading by as many as 24 points.

From there, the Pacers toyed with the Nets, with Paul George — who finished with 26 points, six rebounds and five assists — at one point throwing down a double-pump reverse slam that wouldn’t have looked out of place in the NBA’s Slam Dunk contest, while Brooklyn native Lance Stephenson had 26 points, seven rebounds and five assists, including a beautiful dish off a drive to Luis Scola.

“They tend to play better in the second half,” Kidd said of the Pacers. “When you look at [Paul] George, he’s played his best in the second half, and that’s what they did there in that third quarter.

“A lot of it was our turnovers that led to layups on the other end, where we couldn’t set our defense. That kind of put us in the hole.”

Now with twice as many wins as losses, the Nets have dug themselves into a massive hole. And if it was even a question before Monday night’s loss, with Lopez now gone for the rest of the season escaping from it is going to be even harder than they thought.